4-(2-ethoxybenzoyl)-8-methyl-1-oxa-4,8-diazaspiro[4.5]decane-3-carboxylic acid

8-ethyl-4-(4-fluorobenzoyl)-1-oxa-4,8-diazaspiro[4.5]decane-3-carboxylic acid

8-Ethyl-4-(2-fluorobenzoyl)-1-oxa-4,8-diazaspiro[4.5]decane-3-carboxylic acid

8-ethyl-4-[3-(trifluoromethyl)benzoyl]-1-oxa-4,8-diazaspiro[4.5]decane-3-carboxylic acid

8-ethyl-4-(naphthalene-2-carbonyl)-1-oxa-4,8-diazaspiro[4.5]decane-3-carboxylic acid

8-ethyl-4-(pyridine-3-carbonyl)-1-oxa-4,8-diazaspiro[4.5]decane-3-carboxylic acid

4-(2-phenylacetyl)-8-propyl-1-oxa-4,8-diazaspiro[4.5]decane-3-carboxylic acid

4-(4-tert-butylbenzoyl)-8-propyl-1-oxa-4,8-diazaspiro[4.5]decane-3-carboxylic acid

4-(3-phenylpropanoyl)-8-propyl-1-oxa-4,8-diazaspiro[4.5]decane-3-carboxylic acid

4-(2,4-difluorobenzoyl)-8-propyl-1-oxa-4,8-diazaspiro[4.5]decane-3-carboxylic acid

4-benzoyl-8-tert-butyl-1-oxa-4-azaspiro[4.5]decane-3-carboxylic acid

8-propyl-4-(2,4,6-trimethylbenzoyl)-1-oxa-4,8-diazaspiro[4.5]decane-3-carboxylic acid

8-tert-butyl-4-(naphthalene-2-carbonyl)-1-oxa-4-azaspiro[4.5]decane-3-carboxylic acid

8-tert-Butyl-4-(2,4-difluorobenzoyl)-1-oxa-4-azaspiro[4.5]decane-3-carboxylic acid

8-tert-butyl-4-(4-chloro-2-fluorobenzoyl)-1-oxa-4-azaspiro[4.5]decane-3-carboxylic acid